1. Field of the Invention
The present invention relates to novel and improved corner constructions for connecting adjacent panel walls, to drawer constructions employing the novel and improved corner constructions, and to methods of forming corner and drawer constructions.
2. Prior Art
In the manufacture of sliding drawers and other box-like containers having upstanding walls surrounding a bottom panel, it is known to form selected ones of the upstanding walls from plastics material. Drawers for kitchen cabinets, for example, commonly employ sides and backs formed from hollow, extruded plastic strips, and fronts formed from wood, chipboard, or other decoratively finished material.
A problem commonly encountered in the fabrication of drawers and other containers of this type is that of forming secure, rigid, attractive corner connections between adjacent, upstanding, extruded plastic wall members. Another problem is that of forming secure, rigid and attractive connections between drawer fronts formed of decoratively finished material and drawer sides formed of extruded plastics material.
A common approach which has been taken in an effort to provide good corner connections between adjacent, upstanding, extruded plastic wall members calls for the use of corner connection pieces having formations which extend into hollow ends of the wall members. Both rigid and hinged corner connection pieces have been proposed, and most proposals call for the corner pieces to be formed by injection molding.
The approach of using corner connection pieces has several drawbacks. Difficulties are encountered in maintaining a good color match between the extruded wall members and the injection molded corner pieces. Since wall members of different heights are required to provide drawers of a variety of depths, the manufacturer is required to maintain an inventory of many different sizes of corner connection pieces. Still another drawback of this type of corner connection approach is that the tolerances involved in forming the various interfitting components often result in the formation of loose fitting connections among the components. Even where tight fitting connections result, the presence of a plurality of joint connection cracks on the inside and outside surfaces of the drawer at each corner location gives an undesirable appearance.
Another approach which has been proposed is that of forming adjacent ones of the upstanding walls integrally from a single extruded plastic strip. The referenced Drawer Patent describes one proposal of this type, but does not address the problem of providing smooth inner and outer surface corner connections between adjacent upstanding walls formed from hollow plastic extrusions. Another proposal of this type has called for the use of 45 degree cuts made in the inner wall surface of a hollow extruded strip to form V-shaped miter grooves that will permit the strip to be folded at corner locations to form right-angle corners between the sides and back of a drawer. This latter proposal utilizes a folding corner block assembly which is inserted into the hollow ends of the sides and back. After the corner block is inserted, the corner assembly must be glued to maintain its rigidity, and the corner crack formed on the inside drawer surface must be filled to give an acceptable appearance.
Attempts to provide suitable integral corner connections between adjacent upstanding walls formed from hollow, extruded plastics material have not achieved good commercial acceptance. The hollow, extruded plastics material used to form drawer sides and backs have inner and outer walls that vary to some degree in thickness and spacing. Moreover, the inner and outer wall surfaces are seldom perfectly flat. No matter how carefully conventional V-shaped miter grooves are formed in these materials, many of the resulting folded corner formations will have unevenly mating inner edges presenting unsightly corner cracks.
In some drawer construction applications, it is desirable to form rigid, locked corner connections between adjacent upstanding wall members. A problem common to all known prior corner connection proposals which provide rigidly locked corner connections is that they are not well adapted for field assembly. Where a plurality of parts are required to form corner assemblies, it is not uncommon for some of the parts to be lost or misplaced or broken during shipment and assembly, causing delays while replacements are obtained. Where the assembly steps require the use of bonding agents of separately inserted pins or other fasteners, the possibility of improper field assembly is of concern. Gluing and crack filling operations are time consuming and tedious even when carried out in a controlled factory environment by experienced workmen, and these operations are not well adapted for use by inexperienced personnel at an installation site.